Electromagnetic transducers are widely used to convert electromagnetic energy into translational motion. Common categories of transducers include moving coil designs and moving armature designs, so named for the primary moving elements of each. The latter designs are often referred to as variable reluctance devices, as the magnetic reluctance, or the ratio of magnetomotive force to magnetic flux, varies as the magnetic armature moves in relation to a fixed magnetic structure.
Variable reluctance devices are frequently used in various applications including agitators, acoustic devices, and sensors. In these applications, a device should operate efficiently, such that large translational forces are converted efficiently from an applied excitation current. A device should also operate linearly, such that a flat translational response is produced over a broad range of excitation frequencies.
Like reference symbols in the various drawings indicate like elements.